Since arriving on the Red Planet in 2005, the solar-powered robot has journeyed across 40 kilometres of Martian terrain.
That surpasses the previous record, held by the Soviet Union's Lunokhod 2 rover, which landed on the Moon in 1973.
"Opportunity has driven farther than any other wheeled vehicle on another world," said Mars Exploration Rover Project Manager John Callas of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California yesterday.
"This is so remarkable considering Opportunity was intended to drive about one kilometre and was never designed for distance."
Opportunity and its twin rover, Spirit - now defunct - discovered wet environmental conditions on ancient Mars, some of which are mild enough to have been favorable for life.
Opportunity is now exploring the Endeavour Crater on Mars.
Its next-generation robotic counterpart, the Curiosity rover, launched in 2012 and is tooling around near the Gale Crater on Mars.
NASA said that the Soviet Union's Lunokhod 2 rover landed on Earth's moon on January 15, 1973, and drove about 39 kilometres in less than five months.
Those figures are based on calculations recently made using images from NASA's Lunar Reconnaissance Orbiter (LRO) cameras that reveal Lunokhod 2's tracks, the US space agency said.